Toroidal props

[Dick Byron]

I am sure this could be adapted to our use. Toroidal props.

[Lyle Spiegel]

I look forward to reading abouty first flight using this type prop

[bill bischoff]

was there supposed to be an attachment? 

[Dick Byron]

No just do a GOOGLE search.

[Paul Wescott]

I agree they could be used in Control Line but why?  Do we really need quieter props?  I don’t think propellers are causing our noise problem.  Am I wrong?

PW

[Steve Berry]

From what I've read and heard, they are not just more quiet, they are more efficient. On an electric, I've heard up to 20% more efficient, which could translate into saving an ounce or two on the battery by not needing as big of one.

Big down side, though, is it looks like they are mostly 3D-printed, which may or may not hold up to our abuses, I mean, uses...at least for a prop.  However....I supposed you could 3D print one, test it to see how well it works, and then use it to make a mold for a carbon fiber version.

Now, to find a spinner for such a critter.....

Steve

[Gerald Arana]

was there supposed to be an attachment? 

They look like a "Boat" propeller.

Jerry

[Ken Culbertson]

Very interesting.  I hope someone tries one of these.  One thing I have been curious about.  We are not supposed to use props made for drones.  I don' t intend to but Why?  Do they run at lower RPM?  What is there besides RPM that determines if a prop is or is not appropriate for CLS?

Ken   

[Brett Buck]

Very interesting.  I hope someone tries one of these.  One thing I have been curious about.  We are not supposed to use props made for drones.  I don' t intend to but Why?  Do they run at lower RPM?  What is there besides RPM that determines if a prop is or is not appropriate for CLS?

Ken

   On an IC motor, there are extremely large variations (100xish the average running torque) in the torque through a rev and a firing and everyone is concerned with these torque variations flexing and fatiguing the prop near the hub.

    For electric, the danger is a prop strike removing a blade, because they are extremely brittle and there have already been several examples of light prop strikes that caused the blade to fling off. There's not a lot of danger to people but it will definitely destroy the airplane in very short order from vibration. The various FRP  electric props are also not a good idea for IC for the fatique reason, but they are much tougher and a prop strike will not usually cause them to throw the entire blade.

        Brett

[Air Ministry .]

Theyd look good on one of these . 



 




. Wonder about the MASS , gyro effect . Seems to be variable blade types .




Then we could . . .



The ones with the flat ring around the outside - revolving - make it harder to chew your fingers up .

[Air Ministry .]

Some might be more practical . 






Right, PROPS was it .

[wwwarbird]

 I'll be sticking with the same old mousetraps. 

[GallopingGhostler]

Enjoyed the posting of the new toroidals, wasn't aware they existed, seems promising. However until the newer technology becomes more available and affordable, (which seems still a ways off at our level), I'm sticking with the older, less effective but proven props. I gather that perhaps a better application may be in model boating, where it seems it would really shine. In that venue, the smaller sizes would be easier to manufacture.